terminal: prompt to kill remote if process exited (go-delve#1621)

pkg/terminal/terminal.go

@@ -3,6 +3,7 @@ package terminal
 import (
 	"fmt"
 	"io"
+	"net/rpc"
 	"os"
 	"os/signal"
 	"runtime"
@@ -353,6 +354,18 @@ func (t *Term) handleExit() (int, error) {
 
 	s, err := t.client.GetState()
 	if err != nil {
+		if isErrProcessExited(err) && t.client.IsMulticlient() {
+			answer, err := yesno(t.line, "Remote process has exited. Would you like to kill the headless instance? [Y/n] ")
+			if err != nil {
+				return 2, io.EOF
+			}
+			if answer {
+				if err := t.client.Detach(true); err != nil {
+					return 1, err
+				}
+			}
+			return 0, err
+		}
 		return 1, err
 	}
 	if !s.Exited {
@@ -404,3 +417,9 @@ func (t *Term) loadConfig() api.LoadConfig {
 
 	return r
 }
+
+// isErrProcessExited returns true if `err` is an RPC error equivalent of proc.ErrProcessExited
+func isErrProcessExited(err error) bool {
+	rpcError, ok := err.(rpc.ServerError)
+	return ok && strings.Contains(rpcError.Error(), "has exited with status")
+}

pkg/terminal/terminal_test.go

@@ -1,6 +1,8 @@
 package terminal
 
 import (
+	"errors"
+	"net/rpc"
 	"runtime"
 	"testing"
 
@@ -85,3 +87,21 @@ func TestSubstitutePath(t *testing.T) {
 		}
 	}
 }
+
+func TestIsErrProcessExited(t *testing.T) {
+	tests := []struct {
+		name   string
+		err    error
+		result bool
+	}{
+		{"empty error", errors.New(""), false},
+		{"non-ServerError", errors.New("Process 33122 has exited with status 0"), false},
+		{"ServerError with zero status", rpc.ServerError("Process 33122 has exited with status 0"), true},
+		{"ServerError with non-zero status", rpc.ServerError("Process 2 has exited with status 25"), true},
+	}
+	for _, test := range tests {
+		if isErrProcessExited(test.err) != test.result {
+			t.Error(test.name)
+		}
+	}
+}